The present invention relates to an electronic component, a laser device, an optical writing device using the laser device and an image forming apparatus using the optical writing device.
1. Technical Field
In a laser device, a seal body (cap) is fixed to a base (eyelet), and hermetically sealed space is formed with the base and the seal body. A laser light emitting element or the like as an electronic component main body is placed within the hermetically sealed space.
2. Related Art
An electronic component having a base, a seal body fixed to the base, forming hermetically sealed space together with the base, and an electronic component main body attached to a metal substrate via an adhesive containing silver within the hermetically sealed space, has inconvenience of leakage of minute electric current between an anode and a cathode of the electronic component.
The present inventors have found that sliver migration causes leakage of minute electric current. The silver migration means a phenomenon that ionized silver is precipitated in an insulating layer by electrochemical reaction to direct-current electric field. The silver migration generally occurs by moisture in atmosphere.
However, the present inventors have found another factor of the silver migration. That is, as shown in Japanese Published Unexamined Patent Application No. Hei 11-354685, when an electroless nickel plated layer is formed in the base, phosphor in the electroless nickel plated layer is discharged into the hermetically sealed space by heat in fixing of the seal body to the base by resistance welding or brazing. As the phosphor discharged in the hermetically sealed space has a high moisture absorption characteristic, it absorbs moisture in the hermetically sealed space and is ionized. It can be considered that the ionized phosphor further ionizes silver of the silver paste, thus causing silver migration.